Go inside to really appreciate this 500-year-old technological masterpiece.

The only museum with its curator—and her pets—buried inside.

Art and armour fill every inch of this rich kid's Italian villa.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

More than 450 years ago, an Italian nun became the first woman to paint the iconic subject.

The world's longest and deepest train tunnel.

The mark of the Devil's horns on a marble column in Milan.

Massive galleon from a box-office bomb docked in Genoa.

This grisly effigy displays an early Christian martyr who was skinned alive and beheaded.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

Once home to one of the oldest banks in the world, this building is also where Marco Polo's famous travelogue was written.

This cathedral hides a sculpted dog that determines your fate and an unexploded shell from World War II.

An image of the legendary saint stands in the shadow of a cathedral she liberated.

One of Jeff Koons’s largest sculptures and his first commemorative work.

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

Indents in the pavement are all that remain from a grisly death machine in Paris.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the 20th century.

This massive library holds what was once the largest book collection in the world.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

This demon atop the Notre-Dame de Paris looks utterly bored.